For FY19, we developed a method to determine the structure of nucleosome core particles at atomic resolution, which uses a single chain antibody (scFv) to stabilize the nucleosome core particle. Using this method, we determined the structure of the human centromeric nucleosome core particle containing the native DNA sequence at 2.6 A resolution. The high resolution structure allows us to identify new features of the nucleosome core particle. We also determined the structure of the nucleosome core particle in complex with the chromatin remodeler ISWI in a primed state. The structure provides insights into the catalytic mechanism of the remodeler.